1. Field of the Invention
The present invention is generally directed to a system for temporarily shoring up an excavation site. More particularly the invention is directed to a corner connection used in a reinforcing arrangement that supports sheet piling in an excavation site.
2. Description of the Prior Art
In a typical excavation site, workers are exposed to numerous hazards. The most common hazard is having the walls of the excavation site cave in on the workers, thus causing serious injury. Often due to soil conditions and wetness, the sides of a construction site will simply collapse. Water is a particularly dangerous hazard because it is so heavy and can destroy shoring which has not been properly reinforced. Realizing this problem the government, at both the federal and state level, has set up specific requirements for all excavation sites to avoid the problem of cave-ins. For example the United States Department of Labor and, more specifically, the Occupational Safety and Health Administration (OSHA) requires that excavation sites be prepared with some type of shoring. Additionally many companies are now aware of the problems involved in a typical excavation site and have developed internal policies requiring shoring for any excavations they contract to have completed.
A good example of a typical excavation project would be found in replacing underground storage tanks for a gasoline station. Typically, in such an operation, sheet piling is pounded into the ground in a generally rectangular configuration around the work site. The piling has to be driven extremely deeply into the ground and arranged to provide sufficient support against potential cave-ins. Typically the sheet piling has to be driven so that half its total height remains underground after the excavation has been completed. Use of such large amounts of material is quite expensive. After the sheet piling has been installed, the workmen then remove the dirt and fill material from within the rectangular shoring. During the work of removing the old storage tanks and replacing them with new storage tanks the shoring provides protection to the workmen against potential cave-ins. Once the storage tank replacement operation has been completed the shoring can either be completely removed or simply cut down two a safe distance below ground and then left in place. Such a method of shoring an excavation site is extremely expensive.
Various solutions have been proposed in an attempt to cut down on the costs of shoring an excavation site. For example U.S. Pat. No. 5,154,541 discloses a modular earth support system. Specifically the patent teaches using panels which are adapted to be placed around an excavation site and interlocked with one another to form a generally rectangular shoring configuration. Once the panels are in place, reinforcing beams are placed behind the panels to ensure the weight and force of the dirt behind the panels does not cause the panels to fail. The main drawback of using such a system is that standard I-beams cannot be used. Rather, special beams which are cut exactly to size and additionally have a customized end configuration must be used. Such beams are particularly expensive, especially considering a large number of beams of varying sizes would have to be kept available for differently sized excavation sites.
Another proposed solution to reducing the high cost of shoring excavation sites can be found in U.S. Pat. No. 4,685,837. This patent proposes using panels as shoring members in an excavation site. The panels are reinforced by using laterally extending braces. The braces are connected to one another by a bracket or the braces maybe connected to each other by means of a connection in which one brace has a pair of tabs welded thereto with each tab having an aperture formed therein. The apertures align with a hole in a second brace and a pin is placed though the apertures to complete the connection. In either case there is no provision to adjust the length of the braces and connectors and they must be custom made for each different sized excavation site.
Numerous other proposed solutions are available including using wooden shoring which is a custom made to a particular excavation site. Such shoring is used only at the designated site and then disposed of. As a result this approach is prohibitively expensive. Also wooden shoring is not as durable as its metal counterparts. Often water along with regular wear and tear at the construction site can destroy the shoring during the construction job.
Based on the above, therefore there exists a need in the prior art of excavation shoring to provide a system wherein shoring can be provided at an excavation site in an inexpensive and reusable manner which does not suffer the disadvantages of the prior art discussed above. More specifically there exists in the in the art to provide a connector for interconnecting various beams used to reinforce shoring in a manner which enables the shoring to be adjusted easily or at least matched readily to the size of different excavation sites and additionally be reusable.